Tuning mechanism



Patented June 1,8, 1.940

narran STATES PATENT OFFICE TUNING MECHANISM Application October 15,1937, Serial No. 169,103 In the Netherlands December 11, 1936 3 Claims.

It is known to provide the tuning mechanism of radio receiving sets withan inertia mass (ilywheel) so that in case of the tuning knob beingdriven in a jerky manner it continues moving by r the action of theilyheel without any further attendance. Such a device is of particularimportance for apparatus comprising a transmission between the tuningknob and the condenser, since otherwise the tuning in such apparatus,

10 especially from one station to another station where stations arewidely spaced in the frequency spectrum, would occupy much time. In theknown devices the said inertia mass is directly mounted on the shaft ofthe tuning knob. In order to obtain the effect aimed at this inertiamass should be very large which involves structural difficulties.

The present invention consists in that the flywheel, or the brakingdisc, is mounted on a separate shaft which is driven and accelerated bythe shaft of the tuning knob. Owing to this the flywheel may be given avery small size.

Furthermore, the invention is of great importance for devices, known perse, comprising a brake which, after establishment of correct tuning to-a carrier wave, automatically operates by the action of the incomingsignal. Such a system is shown, for exampla'zby C. J. Van Loon, PatentNo. 2,108,420, issued on Feb. 15, -1938. It has turnedout to beextremely efficacious to drive the brake disc, according to theinvention, in an accelerated manner While using the brake disc as aflywheel at the same time, if desired. It will be appreciated that it isdesirable to stop the tuning condenser as rapidly as possible uponestablishment of accurate tuning. This can now be accomplished by,proceeding according to the invention. By a judicious choice of theflywheel and the brake it can be ensured that the angle over which thecondenser turns` further after operating the brake, remains limited tosuch a value that the tuning is substantially no longer effected. Owingto this the dimensions of the whole braking device are materiallyreduced.

The invention will be more clearly understood by reference to theaccompanying drawing.

In this drawing the tuning knob l is secured to the shaft 2, which hasmounted on it a toothed wheel 3 having a comparatively large size, and a50 pinion 4. Two shafts 5 and 6, carrying the toothed wheel l and thepinion 8 respectively, are journalled in the frame. The tuning condenser9 is secured to the shaft 5, whereas the shaft 6 carries the flywheelI0.

y,Upon turning the tuning knob the shafts 2, 5

and 6 are operated simultaneously. If the tuning knob is jerkily driventhe flywheel l provides that the system of axes, and the members`mounted thereon, continue moving without any further attendance. Due tothe fact that the movement of the shaft 6 is greatly acceleratedrelatively to the shaft 2, a flywheel having a comparatively small sizeis suflicient. The shaft 2 is given a greatly accelerated movementrelatively to the shaft so that when the disc I0 is used as a brakedisc, which may for instance be effected by making the flywheel lll frommagnet material and by subjecting it to the action of a Ibraking magnetll, the substantially unavoidable angular rotation of the brake discafter operating the brake will not affect the tuning. In fact, the saidrotation will be transferred in a highly retarded manner to thecondenser shaft.

What is claimed is:

l. In a tuning mechanism for a radio receiving set provided with atuning condenser, a driving shaft and a plurality of driven shafts allarranged in parallel, the tuning condenser being mounted on one of thedriven shafts, a combined flywheel and brake disc of magnetic materialmounted on a second driven shaft,l a braking magnet responsive toincoming signals cooperatively related with said combined flywheel andbrake disc and gearing means separately interconnecting each drivenshaft with the driving shaft such that rotation of the latter shaft at acertain speed causes the first driven shaft to rotate at reduced speedand the second driven shaft to rotate at increased speed with respect tothe driving shaft.

2. In a tuning mechanism for a radio receiving set provided with atuning condenser, a driving shaft and a plurality of driven shafts, thetuning condenser being mounted on one of the driven shafts, a fly wheelof magnetic material mounted on a second driven shaft, a braking magnetresponsive to incoming signals cooperatively related with said flywheel,a large gear and v a small gear mounted on the driving shaft, a largegear mounted on the driven tuning condenser shaft meshing with the smallgear of the driving shaft, and a small gear on the driven flywheel shaftmeshing with the large gear of the driving shaft. Y

3. Tuning mechanism for radio receiving sets comprising a driving shaftand a pair of driven shafts all arranged in parallel, a tuning condensermounted on one of the driven shafts, a combined flywheel and brake discof magnetic material mounted on the other of said driven shafts, abraking magnet cooperatively related with said brake disc, a large gearand a small gear mounted on the driving shaft, a large gear mounted onthe driven tuning condenser shaft meshing with the small gear of thedriving shaft, and a small gear on the driven fly-Wheel and brake discshaft meshing with the large gear of the driving shaft, the arrangementbeing such that rotation of the driving shaft causes rotation of thetuning shaft at reduced speed and the brake disc at increased speed,whereby slight continued angular rotation of the brake disc uponoperation of the brake magnet at the desired tuning position of thetuning condenser will have no substantial eiect on said tuning position.

GUNNAR BORGE KNOS. ALEXANDRE HOROWITZ.

